A process and engine using a homogeneous mixture of fuel and air but ignited spontaneously by high mixture temperatures produced by heating and by compression of the fuel charge in which a controlled rate of combustion is obtained by adding exhaust products to the fuel-air mixture. A combustion chamber is connected to the cylinder head of an internal combustion engine which is provided with a fuel and exhaust products which remain therein as fresh air is introduced into the cylinder due to a restricted entrance. A heater element at the entrance heats fresh air entering the combustion chamber on the compression stroke to produce spontaneous ignition of the homogeneous mixture.
Charles D. Wood